Molecular design rules for wettability minimisation on grafted cellulose surfaces through human-machine teaming...

Area of Science:

• Interfacial Materials Science
• Polymer Chemistry
• Computational Materials Design

Background:

• Controlling surface wettability on cellulose is crucial for advanced interfacial materials.
• Graft molecular structure's influence on cellulose wettability is not fully understood.
• Hypothesis: Local branching and steric organization are more critical than molecular size or aromaticity for reducing wettability.

Purpose of the Study:

• To investigate the relationship between graft molecular structure and cellulose surface wettability.
• To identify optimal graft designs for minimizing surface wettability.
• To establish molecular design rules for hydrophobic cellulose surfaces.

Main Methods:

• Utilized all-atom molecular dynamics (MD) simulations to calculate water contact angles on grafted cellulose.
• Employed a human-machine teaming molecular optimization strategy with latent-space Bayesian optimization.
• Conducted targeted perturbation studies on branching density, position, and heavy-atom count.

Main Results:

• Identified a narrow hydrophobic design window for grafted cellulose surfaces.
• Compact, densely branched aliphatic grafts achieved water contact angles >110°, outperforming elongated and aromatic grafts.
• Optimal structures featured localized steric bulk near the grafting point and limited heavy-atom counts.

Conclusions:

• Physically interpretable molecular design rules for wettability minimization on grafted cellulose were established.
• Compact, branched aliphatic structures are superior for achieving hydrophobicity.
• The study provides an efficient method for identifying high-performing grafts, even with limited data.